Separation of piled metal sheets



Aug. 19, 1958 K. H. GULICK SEPARATION OF PILED METAL SHEETS Filed Sept.12, 1955 M M T E N N E K}.

ATTORNEYS United States Patent SEPARATION OF PILED METAL SHEETS KennethH. Gulick, Northfield, Ohio, assignor to Harris- Intertype Corporation,a corporation of Delaware Application September 12, 1955, Serial No.533,640

2 Claims. (Cl. 271-18) This invention relates to improvements inseparation of piled metal sheets, and has to do with a novel means andmethod in which air blasts are combined with a particular flow ofmagnetic current to make possible elfective sheet separation.

The use of magnets along the sides of a pile of metal sheets to separatethe edges of the uppermost sheets is well known in the art. Magnetsemployed in this way and for this purpose are successful, especially forsheets that are relatively narrow, but as the width of the sheetsincreases a greater and greater part of the intermediate portion of eachsheet sags down and rests heavily upon the next sheet therebeneath. Thusthe separation of the uppermost sheets is not complete and the tendencyfor them to stick together as the top sheet is fed off presents adifficult problem. oftentimes, the sheets are treated with an oil filmto prevent rusting. This also causes the sheets to adhere to one anotherand makes proper sheet separation difiicult.

The top of the pile must be maintained approximately at a given level,that is to say the level of the pull out rolls through which each sheetpasses as it leaves the pile. It is not feasible to raise the pile theminute dis tance equivalent to the thickness of a sheet for each feedcycle, but by means of a feeler control the body of the pile may beraised intermittently to maintain it Within upper and lower limits aquarter or half inch apart.

The present invention utilizes improvements for combining air blastswith magnetic separation so as to make the separation efiective forlarge sheets. The air blast nozzles, which may be flattened vertically,are fixed at a predetermined height, as are also the magnets. In orderto obtain the best results from the air blasts, the nozzles should beequally effective with the pile at the low limit as well as at the highlimit. I have discovered that this is possible if magnet means isarranged in a particular manner, that is with the poles spacedvertically. When this is done the edge of each top sheet as it becomesthe top sheet rises to a given fixed level, and it does this in spite ofthe fact that the level of the central part or body of the pile changesbetween high and low limits through a distance of the order ofone-quarter or onehalf inch.

I dispose the magnets at a height such that the side edge of the topsheet at the high limit of the pile will be somewhat above the body ofthe pile, so that whatever the height of the body of the pile may be,the side edges of the uppermost sheets will be fanned out vertically.The air blast nozzles are fixed in position and mounted at a height suchthat they will blow air inwardly through the fanned out edges of theuppermost sheets mainly below the top sheet, the side edge of which isdisposed at a height dependent upon the action of the magnet means.

I have found that it is possible to bring about the positioning of theside edge of the top sheet at an unvarying level only when the magnetmeans comprises a pair of vertically spaced magnetic poles. This isaccom- 2,848,227 Patented Aug. 19, 1958 ice plished conveniently byusing horseshoe magnets. The side edge of the top sheet of the pile thentakes a position approximately even with the lower edge of the upperpole of the magnet. Horizontal mounting of the magnets will notaccomplish the purpose satisfactorily, for then the level of the sideedge of the top sheet is not constant but descends as the level of thebody of the pile descends from its upper limit toward its lower limit.If that condition obtains the force of the air blast is dissipated byflow above the top sheet, and sheet separation is not satisfactory. f

One of the objects of the invention therefore is the provision of novelmeans for effecting separation of magnetizable sheets preparatory totaking the top sheet and feeding it off the pile.

Another object is the provision of combined magnetic and air separationsuch as to insure correct separation and feeding throughout variationsin the height of the body of the pile due to intermittent action of pileelevating mechanism.

Other objects and features of novelty will appear as I proceed with thedescription of that embodiment of the invention which, for the purposesof the present application, I have illustrated in the accompanyingdrawing, in which Fig. 1 is a fragmental perspective view of a pilefeeder embodying the invention.

Fig. 2 is a detail elevational view of a fragment of a pile withelements of the sheet separating means of the invention in operativerelation to the pile, the body of the pile being shown raised to itshigh limit.

Fig. 3 is a view similar to Fig. 2 after the body of the pile hasdescended to its low limit and is about to be raised.

As sheet metal feeders of the type with which this invention is to beused are well known in the art, only so much of the feeder is hereinillustrated as is believed to be necessary for a complete understandingof the invention by those skilled in the art.

Referring to Fig. 1, a pile of sheets 10 responsive to magnetic lines offorce, is carried on a pile support 11 of a pile feeder for magnetizablesheets. The pile support comprises side arms 12 and 13 which may beI-beams connected at their forward ends by a crossbar 14 and similarlyconnected at their rear ends. Each of the arms 12 and 13 is providedwith a pair of brackets 15, these brackets being supported by cables 16of the pile feeder. It is to be understood that the pile support 11 isprovided with means for raising it intermittently during automaticfeeding in response to control by pile height governing means tomaintain the top of the body of the pile between predetermined high andlow limits.

This means preferably embodies a pile height feeler 17 which engages thebody of the pile along the median line thereof near the rear edge of thetop sheet. This feeler rises to permit the top sheet to be drawn olf andthen descends to engage the next sheet therebeneath. When a number ofsheets have been withdrawn suflicient to reduce the level of the body ofthe pile to a predetermined low point, electric switch means operated bythe feeler effects controls which cause the pile to rise to itspredetermined high limit. The details of such control means are fullydisclosed in my copending application Serial No. 553,556, filed December16, 1955.

Along each side of the pile of sheets 10 there are fixedly mounted aplurality of horseshoe magnets 18 and their upper and lower poles 19 and20 facing toward the pile and disposed closely adjacent thereto.Preferably guide plates 21 of non-magnetic material, such as brass, aresupported by the magnets. The side edges of the pile may nearly bearagainst these plates. While permanent magnets are shown, electromagnetsmay be used if desired.

As is conventional in the art the top sheet is grasped by suckers 22which descend at the proper time in the cycle and lift the forward endof the sheet, after which a pair of suckers 24 take the sheet, thesuckers 22 letting go. Suckers 24 then advance, carrying the front edgeof the sheet into the bight of pull outrolls 25, 26 of conventionalconstruction and operation. The rolls 26 swing up and down through asmall arc to admit the sheets one after another and to provide tractionfrom the continuously driven rolls 2S.

At each side of the pile there are air blast nozzles 28, each pair ofmagnets having a nozzle between them. Preferably the air blast iscontinuous. The magnets on opposite sides of the blast nozzle hold theedge of the top sheet at the level indicated at 30 in Fig. 2, and fanout several of the uppermost sheets below the top sheet. The air flowsinto the pile between adjacent fanned out sheets and below the topsheet, tending to float the latter and facilitate its movement oil thepile by the advancing suckers 24.

Operation. Assuming that the body of the pile is in the high limitposition, as indicated in Fig. 2, with the uppermost sheets of the pilefanned out vertically by the action of the magnets and air nozzles, thelifting suckers 22 grasp the top sheet and raise it to a level where theadvancing suckers 24 may take it. The latter suckers then carry itsforward edge into the bight of pull out rolls 25, 26, which impel itforward. As soon as the sheet being fed uncovers the next sheettherebelow, the edges of the latter sheet rise to the position indicatedat 30 in Fig. 2 and the described procedure is repeated, a new sheetbeing added to the bottom ofthe series of fanned out sheets. When thelevel of the body of the pile descends sufliciently because of thesheets that are fed off, the condition of the pile represented in Fig. 3is arrived at. Here the body of the pile is shown at its low limit, inother words at the point where the feeler 17 acts to bring about theelevation of the pile from its low limit to its high limit. However,between the conditions represented in Figs. 2 and 3, the side edges ofthe top sheet at each stage of operation rise to the height indicated at30 in Figs. 2 and 3, and the air continues to pass into the spacesbetween the fanned out sheets without any appreciable loss of airflowing above the top sheet. Hence sheet separation is equally efiectivethroughout the pile movements between the high and low limits indicatedin Figs. 2 and 3.

Having thus described my invention, I claim:

1. In a pile feeder for feeding magnetizable sheets one at a time fromthe top thereof, horseshoe magnets adjacent at least one side edge ofthe pile, said magnets having their magnetic poles vertically spacedapproximately opposite the top of the pile, means for maintaining thetop level of the body of the pile between pre-v determined high and lowlimits, said magnets holding the side edges of the uppermost sheetsfanned out with the edge of the top sheet at approximately the samelevel regardless of the level of the body of the pile, air blast meanslocated at a fixed level adjacent the top of the pile and directed toblow air into the pile through the fanned out edges of the sheets belowthe edge of the top sheet, and means for taking the top sheet andfeeding it from the pile.

2. In a sheet feeder for feeding magnetizable sheets one at a time fromthe top of a pile, permanent horseshoe magnets on opposite sides of thepile, said magnets having their magnetic poles vertically spacedapproximately opposite the top of the pile, means for maintaining thebody of the pile with its top level between predetermined high and lowlimits, said magnets holding both side edges of the uppermost sheetsfanned out with the edges of the top sheet at approximately the samelevel throughout variations in the level of the pile, air blast means onboth sides of the pile located at a fixed level adjacent the top of thepile and directed to blow air into the pile through the fanned out edgesof the sheets below the edges of the top sheet, and means for taking andforwarding the top sheet from the pile.

References Cited in the file of this patent UNITED STATES PATENTS1,548,000 Finigan July 28, 1925 1,870,314. Lincoln Aug. 9, 19322,650,092 Wall Aug. 25, 1953

